The present invention relates to the dynamic absorber for disc player such as CD disc player or DVD player.
It is well known that a key to achieve a much higher operation speed of a disc player is to limit the vibration generated from the rotation source within the disc player during high speed operation. Typically, there are four categories as stated below with respect to the vibration absorber system of conventional disc player.
As shown in one conventional approach of FIG. 1, a damper (K,C) is provided between the traverse module 11 and tray motion control module 13 to absorb the vibration generated thereof due to the external force F. The damper in the system functions to lower the vibration of the traverse module 11 and then stabilizes the disc read operation. However, since the resonance frequency of the design is much higher than the disc operating frequency, this design induces a much higher vibration on the casing of the disc player. In succession, the vibration of the casing of the disc player induces resonance on the computer casing which houses the disc player. As a result, during high speed operation, the computer casing give rise to a substantial noise according to this approach.
As shown in another conventional approach of FIG. 2, an isolator (K, C) is provided between the traverse module 21 and the tray motion control module 23 to perform the isolation function. The approach successfully reduces the vibration of the disc player casing. However, since the resonance frequency of this design is much lower than the disc operating frequency, this design could not transmit the vibration of the transverse module 21 outwardly and experiences a higher vibration of the traverse module 21. As a result, the disc read operation is not stable in some occasions and the disc speed must be lowered to achieve a stable read operation. It is known in the arts, the isolator differs from the damper in regard to the values of K and C. K is spring constant of the component and C is damping ratio of the component. The isolator has a smaller K value which keeps the vibration within the system generating the vibration. The damper has a bigger K value which lowers the vibration while the vibration is propagated outwardly from the system generating the vibration.
As shown in another conventional approach of FIG. 3 which adopting the concept of the dynamic absorber, the traverse module 31 is connected to the tray motion control module 33 by a damper (K1, C1), and the tray motion control module 33 is further connected to the disc player""s casing 35 by an isolator (K2, C2). In other words, the tray motion control module 33, other than its conventional functions, also functions as a dynamic absorber which absorbs most of the vibration energy of the traverse module 31. The inward or outward movement of the tray (not shown) poses a clearance requirement on the corresponding contact parts of the tray motion control module 33. Therefore, a patting phenomenon is inadvertently created as a result of the tray motion control module 33 acting as the dynamic absorber.
As shown in another conventional approach of FIG. 4, a damper (K1, C1), a dynamic absorber 43 and an isolator (K2, C2) are provided between the traverse module 41 and the tray motion control module 45 to function as the vibration absorber. In this design, the dynamic absorber 43 experiences a substantial vibration while the traverse module 41 and the tray motion control module 45 achieves a much lower vibration. It is important to note that the dynamic absorber 43 is disposed between the traverse module 41 and the tray motion control module 45. Therefore, as the disc player is disposed vertically during operation, the dynamic absorber 43 will be in contact with the tray motion control module 45 due to gravity effect. And due to the vibration of the dynamic absorber 43 is substantial, knocking or patting between the dynamic absorber 43 and the tray motion control module 45 will also be substantial. As the result, during high speed operation, not only the noise thereof is annoying to the user, but the resonance of the computer system""s housing is undesiredly created. On the other hand, the damper (K1, C1) as well as the isolator (K2, C2) are made of the deformable rubber material upon which the assembly dimension accuracy is difficult to impose. An, in this design, dimension tolerances of the damper, isolator, the dynamic absorber and the assembly relationship inherently exist between the traverse module 41 and the tray motion control module 45. In overall, the effective vibration absorbing capability of this design heavily depends on the control of the dimension tolerances mentioned above.
Due to the drawbacks recited above with respect to the conventional approaches, the present invention intends to provide a simple and effective way to lower the vibration associating with high speed operation of the disc player without the drawbacks mentioned above.
A disc player is provided to include a tray motion control module, a traverse module and a dynamic absorber. The tray motion control module supports the tray and, responsive to the instruction, performs in-out operation of the tray. The traverse module, via an isolator, connects to the tray motion control module. The dynamic absorber, via a damper, connects to the traverse module for absorbing the vibration caused by the rotational source on the traverse module. The damper with high damping value transmits most vibration energy from traverse module to dynamic absorber to lower the traverse""s vibration. The isolator keeps the vibration within the traverse module.